Date: Tue, 07 Feb 95 08:34:00 MST
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: M.Radtke@az05.bull.com
Subject: RE: More battery stuff.
Hello,
1) If you are only interested in 12 volts for the refrigerator,
perhaps the refrigerator can be modified for 6 volts. If it is
the usual absorption cycle type, the power is only used for a
heating element and perhaps a light. It might be possible to
modify the existing element, or just to make a new element to do
the job. This should be low tech stuff.
If it is the electronic, Peltier (sp?) type, a bit of rewiring
should do the trick ... two 6 volt strings of diodes rather than
one 12 volt string. This is a bit higher tech.
However, if the refrigerator is of the motor/compressor kind, the
motor is probably sealed and you are out of luck.
2) If the refrigerator can't be modified, or you need other 12 volt
capability, the charge one, then the other trick should be quite
workable. Some set of high current relays would be needed, but the
idea is to charge on battery in parallel with the existing bus
battery with the other 6 volt battery in series with this, adding
to 12 volts for the load. While driving, it would be good to
automatically switch the batteries positions every so often (5
minutes?) to keep the charge and discharge cycles shallow to
preserve battery life. When the engine is off, there is no need
to swap the batteries periodically, but they do need to stay
connected in series to provide power to the 12 volt load. The dumb
refrigerator won't notice the switch at all, but something
electronic, like a radio will experience a moment of discomfort.
In general, I have a lot of difficulty deciding if an how to make posts
here. There seems to be a lot of variation in knowledge among the folks on
this list. So, please forgive me if I have bored you or insulted you
intelligence with my post. Perhaps if anyone wants to discuss this further
we should use email directly.
Mike
Michael A. Radtke - Z74 Voice: 602-862-4897
Bull FAX: 4853
13430 N. Black Canyon Hwy.
Phoenix, AZ 85029 Email: m.radtke@bull.com
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